Allow users to modify specific characteristics and see the fingerprint result based on this modification

[Hainish]

User feedback:

Dear eff,

I want to recommend a useful Feature for the fingerprint test: please make the fingerprints browsable in a way how one can keep some values fixed (e.g. iOS Apple mobile safari) and list the variations in other entropy elements, e.g. Screen size. Some settings in iPhone seem to change fingerprint, and I want to find out how my iPhone is different from other iphone of same model. So one could find uncommon settings active..